1. Field of the Invention
The invention relates to an electric disk-armature motor in accordance with the preamble of claim 1 and an electric bicycle or pedelec comprising a disk-armature motor in accordance with the invention.
2. Background and Relevant Art
In a disk-armature motor, the rotor and the stator have a disk shape. A disk is thin in comparison to its planar extent. The rotor and stator disks of the disk-armature motor are arranged parallel to one another and perpendicular to the axis of rotation of the motor along this axis of rotation. This means that disk-armature motors have a design which markedly differs from the design of other electric motors. Their diameter perpendicular to the axis of rotation is greater than their axial length, generally a multiple greater.
The disk-armature motors on which the invention is based comprise at least one stator in the form of a disk and at least one rotor in the form of an armature disk which is mounted rotatably about an axis of rotation with respect to the stator and/or a motor housing. The rotor (rotor disk) and the stator (stator disk) are oriented parallel to one another and are spaced apart from one another by a gap. An end side of the rotor, which end side faces the stator (the stator disk), has a multiplicity of permanent magnets polarized in the axial direction, which permanent magnets are arranged in the form of a ring around the axis of rotation, wherein a north pole and a south pole faces the stator alternately in the tangential direction. The stator has a multiplicity of coil elements, which are arranged in the form of a ring around the axis of rotation of the rotor.
In known designs, the coil axes of the coil elements are aligned axially in relation to the axis of rotation of the rotor. The coil element is therefore polarized in the axial direction as are the permanent magnets of the rotor, wherein the specific polarization is dependent on the direction of the current flow through the coil wires. Correspondingly, the poles of the coil elements interact with the permanent magnets of the rotor.
One disadvantage with this is that each coil element only ever interacts with a rotor via a pole and therefore a pole face. The coil elements are generally flat coils with a comparatively large cross section, with the result that, correspondingly, the poles also form comparatively large pole faces. This means that disk-armature motors require a comparatively large cross section in order to be able to provide a desired torque.